研究者業績
基本情報
研究キーワード
2研究分野
1経歴
5-
2021年3月 - 現在
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2017年4月 - 2021年2月
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2007年4月 - 2017年3月
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2002年10月 - 2007年3月
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1997年4月 - 2002年9月
受賞
1-
2003年
論文
110-
Analytical chemistry 96(17) 6764-6773 2024年4月30日Tremendous efforts have been made to develop practical and efficient microfluidic cell and particle sorting systems; however, there are technological limitations in terms of system complexity and low operability. Here, we propose a sheath flow generator that can dramatically simplify operational procedures and enhance the usability of microfluidic cell sorters. The device utilizes an embedded polydimethylsiloxane (PDMS) sponge with interconnected micropores, which is in direct contact with microchannels and seamlessly integrated into the microfluidic platform. The high-density micropores on the sponge surface facilitated fluid drainage, and the drained fluid was used as the sheath flow for downstream cell sorting processes. To fabricate the integrated device, a new process for sponge-embedded substrates was developed through the accumulation, incorporation, and dissolution of PMMA microparticles as sacrificial porogens. The effects of the microchannel geometry and flow velocity on the sheath flow generation were investigated. Furthermore, an asymmetric lattice-shaped microchannel network for cell/particle sorting was connected to the sheath flow generator in series, and the sorting performances of model particles, blood cells, and spiked tumor cells were investigated. The sheath flow generation technique developed in this study is expected to streamline conventional microfluidic cell-sorting systems as it dramatically improves versatility and operability.
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Lab on a chip 24(2) 171-181 2024年1月17日Although droplet microfluidics has been studied for the past two decades, its applications are still limited due to the low productivity of microdroplets resulting from the low integration of planar microchannel structures. In this study, a microfluidic system implementing inverse colloidal crystals (ICCs), a spongious matrix with regularly and densely formed three-dimensional (3D) interconnected micropores, was developed to significantly increase the throughput of microdroplet generation. A new bottom-up microfabrication technique was developed to seamlessly integrate the ICCs into planar microchannels by accumulating non-crosslinked spherical PMMA microparticles as sacrificial porogens in a selective area of a mold and later dissolving them. We have demonstrated that the densely arranged micropores on the spongious ICC of the microchannel function as massively parallel micronozzles, enabling droplet formation on the order of >10 kHz. Droplet size could be adjusted by flow conditions, fluid properties, and micropore size, and biopolymer particles composed of polysaccharides and proteins were produced. By further parallelization of the unit structures, droplet formation on the order of >100 kHz was achieved. The presented approach is an upgrade of the existing droplet microfluidics concept, not only in terms of its high throughput, but also in terms of ease of fabrication and operation.
主要なMISC
15-
Colloids and Surfaces B: Biointerfaces 145 152-159 2016年9月1日© 2016 Elsevier B.V. Luminescent particles have been attracting significant attention because they can be used in biochemical applications, such as detecting and imaging biomolecules. In this study, luminescent polystyrene latex particles were prepared through miniemulsion polymerization of styrene with dissolved europium complexes in the presence of bovine serum albumin (BSA) and poly(ethylene glycol) monomethoxy methacrylate as surfactants. The solubility of the europium complex in styrene has a strong effect on the yield of the particle. Europium tris(2-thenoyl trifluoroacetonate) di(tri-n-octyl phosphine oxide), which has a high solubility in styrene, was sufficiently incorporated into the polystyrene particles compared to europium tris(2-thenoyl trifluoroacetonate), which has a low solubility in styrene. The luminescence property of the europium complex could remain intact even after its incorporation through the miniemulsion polymerization. In the aqueous dispersion, the resulting particles could emit strong luminescence, which is a characteristic of the europium complex. The antibody fragments were covalently attached to BSA-covered particles after a reaction with a bifunctional linker, N-(6-maleimidocaproyloxy)succinimide. The time-resolved fluoroimmunoassay technique showed that 3.3 pg/mL of human α-fetoproteins (AFP) can be detected by using the resulting luminescent particles. An immunochromatographic assay using the resulting particles was also performed as a convenient method to qualitatively detect biomolecules. The detection limit of AFP measured by the immunochromatographic assay was determined to be 2000 pg/mL. These results revealed that the luminescent particles obtained in this study can be utilized for the highly sensitive detection of biomolecules and in vitro biochemical diagnosis.
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Colloids and Surfaces A: Physicochemical and Engineering Aspects 482 68-78 2015年10月5日© 2015 Elsevier B.V. Polystyrene latex particles with controlled size were prepared by polymerization of oil-in-water (O/W) emulsion styrene droplets obtained through the phase inversion temperature (PIT) emulsification using amphiphilic comb-like block polymers, polystyrene-b-poly[oligo(ethylene glycol) methyl ether methacrylate] (PStn-b-POEGMAm-Cl). PStn-b-POEGMAm-Cl block polymers were synthesized by sequential atom transfer radical polymerization (ATRP) of St and OEGMA. The interfacial properties of PStn-b-POEGMAm-Cl in aqueous media were investigated by means of surface tension measurement, fluorescence probe technique, and transmittance measurement. The length of hydrophobic PSt block chain was found to affect the critical micelle concentration, the micelle aggregation number, and the cloud point. O/W emulsions were obtained through the PIT process using PStn-b-POEGMAm-Cl as a surfactant by lowering the temperature of emulsions below the PIT in an ice bath. PSt particles with precisely controlled size in a range between 30 and 120nm were successfully prepared by a free radical polymerization of St droplets initiated by the water- or oil-soluble initiators. FE-SEM observation revealed that the morphology of polystyrene particles was found to depend on the relative PSt chain length of PStn-b-POEGMAm-Cl.
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COLLOIDS AND SURFACES B-BIOINTERFACES 29(1) 53-65 2003年5月The adsorption of anti-a-feto protein (anti-AFP) onto polystyrene-core-poly(N-isopropylacrylamide)-shell particles was investigated as a function of temperature, pH, and salinity. The influence of various physicochemical parameters onto the colloidal and surface properties of such stimuli-responsive particles was first studied. Then, the adsorption of anti-AFP antibody was investigated in order to point out the driving forces involved in the adsorption process. The effects of salinity, pH, and temperature demonstrated that adsorption was mainly governed by electrostatic interactions. In addition, the adsorption isotherms were analyzed on the basis of a Langmuir model leading to the determination of affinity constants. Finally, based on this adsorption study, various covalent coupling methodologies of the antibody were compared by using two different copolymers as a reactive spacer arm. The amount of chemically grafted antibody was obtained after performing the desorption step (by lowering the temperature, changing the pH, or raising ionic strength). The grafted quantity of antibody was found to be related to the adsorbed amount as a function of pH and ionic strength. (C) 2002 Elsevier Science B.V. All rights reserved.
Works(作品等)
2共同研究・競争的資金等の研究課題
6-
日本学術振興会 科学研究費助成事業 2021年4月 - 2024年3月
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日本学術振興会 科学研究費助成事業 2018年4月 - 2021年3月
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日本学術振興会 科学研究費助成事業 2001年 - 2002年
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日本学術振興会 科学研究費助成事業 1998年 - 1999年